The present invention generally relates to the manufacture of contact lenses and more specifically relates to molds used in the production of contact lenses, and systems and methods for producing contact lens molds.
One method of manufacturing ophthalmic lenses, such as intraocular lenses and contact lenses, is by cast molding. Cast molding of contact lenses is well known. See, for example, Appleton, et al., U.S. Pat. No. 5,466,147, Morris, U.S. Pat. No. 6,405,993, Dean, U.S. Pat. No. 6,431,706, and Dean, U.S. Pat. No. 6,732,993.
Typically, a mold assembly for producing a single contact lens includes a female mold section having a concave optical surface defining an anterior surface of a lens to be made, and a male mold section having a convex optical surface defining a posterior surface of the lens to be made. When individual male and female mold sections are assembled together, a contact lens shaped cavity is formed between the concave surface of the female section and the convex surface of the male section.
A contact lens precursor material, for example a curable mixture of polymerizable monomers, is placed or deposited within the lens shaped cavity, or more specifically, the lens precursor material is placed in contact with the concave surface of a first mold section and a second mold section is placed on the first mold section so that the convex surface of the second mold section contacts the lens precursor material and maintains the lens precursor material in the lens shaped cavity. The lens precursor material is cured in the mold assembly to form a contact lens. The contact lens is removed from the mold sections and is further treated and eventually packaged for consumer use.
The male and female mold sections used in the above-mentioned contact lens manufacturing process are themselves commonly formed through the use of injection molding processes. These mold sections may be made molded from thermoplastic materials, for example, such as polystyrene or polypropylene, and the like.
Martin et al., U.S. Pat. No. 6,039,899, discloses methods and apparatus for automated high speed manufacturing of contact lens blanks. The apparatus includes an injection molding station for production of contact lens mold sections used to make the blanks.
EP 1136222 A1 discloses methods for the production of contact lenses in which resin molds are formed in a die assembly, the resin molds are then filled with a contact lens molding material, and the filled resin molds are assembled to form contact lenses between the resin molds.
EP 1352736 A1 discloses a contact lens mold assembly comprising multiple, identical, stackable contact lens molds.
Larsen, U.S. Pat. No. 4,565,348, discloses another prior art approach to manufacturing lens molds. Pursuant to this approach, an array of molding surfaces carried on a polystyrene frame are used to form an array of contact lenses. One molded frame carries a 2×4 array of concave front or female mold halves, and another molded frame carries a 2×4 array of convex base or male mold halves.
Additional patents and publications disclosing methods and/or apparatus for manufacturing the molds used in lens manufacture include Lust et al., U.S. Patent Application Pub. No. US 2003/0203066 A1; Lust et al. U.S. Pat. No. 6,592,356; Lust et al., U.S. Pat. No. 5,540,410; and Parnell, Sr. et al., U.S. Pat. No. 6,180,032.
While the aforementioned methods, processes and apparatus have enhanced the speed and efficacy of contact lens manufacturing, there is still a need for even more effective, more efficient processes and systems for meeting the present high demand for contact lenses.